899
FXUS65 KVEF 181206
AFDVEF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LAS VEGAS NV
506 AM PDT THU SEP 18 2025
KEY MESSAGES
* INCREASING TROPICAL MOISTURE WILL MOVE INTO THE REGION TODAY AND
FRIDAY, BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS. LOCALLY
HEAVY RAIN AND HIGH RAINFALL RATES WILL LEAD TO AN INCREASED RISK
OF FLASH FLOODING, ESPECIALLY OVER SAN BERNARDINO COUNTY.
* SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL LINGER THROUGH
THE WEEKEND. DRIER AND WARMER WEATHER COULD RETURN NEXT WEEK.
DISCUSSION
THROUGH WEDNESDAY. EARLY MORNING SATELLITE LOOP SHOWED
MID AND HIGH LEVEL CLOUDS ASSOCIATED WITH THE REMNANTS OF MARIO
BLANKETING OUR CWA. SURFACE OBS SHOWED LIGHT WINDS, A VERY SHARP
DEWPOINT GRADIENT NEAR INTERSTATE 40, AND LIGHT RAIN NEARING OUR
SOUTHERN CWA BORDER. AS HAS BEEN THE CASE FOR A FEW DAYS NOW, THE
INCOMING RAIN IS THE PRIMARY FORECAST CONCERN. HIGH RESOLUTION
MODELS AND WPC PROJECTIONS STILL SHOW THE GREATEST CHANCES FOR HEAVY
RAIN IN SAN BERNARDINO COUNTY, SO WILL LEAVE THE FLOOD WATCH IN
PLACE THERE. LOWER, BUT NONZERO, RISKS FOR FLOODING STILL EXIST IN
THE REST OF OUR CWA, PRIMARILY INYO, CLARK, AND MOHAVE COUNTIES. THE
GREATEST RISK OF FLOODING SHOULD BE TODAY AND TONIGHT BEFORE THE
BEST FORCING EXITS FRIDAY MORNING. LEFTOVER MOISTURE AND MORE
SUNSHINE SHOULD FUEL THUNDERSTORM CHANCES FRIDAY AFTERNOON, THEN
LIMITED TO MAINLY OVER THE MOUNTAINS SATURDAY AND SUNDAY. MODELS
DISAGREE ON WHETHER ANOTHER CUTOFF LOW EARLY NEXT WEEK REMAINS
OFFSHORE OR MOVES INLAND AND TAPS INTO THE TROPICAL MOISTURE LURKING
TO OUR SOUTH. THE FIRST SCENARIO, WHICH LOOKS MORE LIKELY, WOULD
RESULT IN DRIER AND WARMER WEATHER. THE SECOND, WHICH CANNOT BE
RULED OUT, WOULD RESULT IN A ROUND OF MORE WIDESPREAD SHOWERS AND
THUNDERSTORMS.
AVIATION...FOR HARRY REID...FOR THE 12Z FORECAST PACKAGE
LIGHT
AND VARIABLE WINDS WILL CONTINUE THROUGH THE MORNING AS MID-LEVEL
CLOUDS STREAM INTO SOUTHERN NEVADA. VICINITY THUNDERSTORMS EXPECTED
BETWEEN 17 AND 05Z, WITH A 30-40 PERCENT CHANCE OF THUNDERSTORMS
OVER THE TERMINAL CAUSING HEAVY RAIN, FREQUENT LIGHTNING, CIGS
AROUND 8 KFT, AND GUSTY WINDS FROM THEIR DIRECTION BETWEEN 30 AND 40
KTS. WITHOUT THUNDERSTORM INFLUENCE, EXPECT GUSTY SOUTHWEST WINDS
AROUND 20 KTS THIS AFTERNOON, VARIABLE WINDS OVERNIGHT, AND LIGHT
EASTERLY WINDS FRIDAY MORNING. THUNDERSTORM CHANCES RETURN TO THE
REGION FRIDAY AFTERNOON.
FOR THE REST OF SOUTHERN NEVADA, NORTHWESTERN ARIZONA AND
SOUTHEASTERN CALIFORNIA...FOR THE 12Z FORECAST PACKAGE...SHOWER
ACTIVITY WILL CONTINUE THROUGH THE MORNING AT KDAG, KEED, AND KIFP.
AREAWIDE TERMINALS WILL EXPERIENCE VICINITY THUNDERSTORMS BETWEEN 17
AND 05Z TODAY, WITH A 30-40 PERCENT CHANCE OF THUNDERSTORMS DIRECTLY
OVER TERMINALS. WITH DIRECT THUNDERSTORM IMPACT, EXPECT HEAVY RAIN,
FREQUENT LIGHTNING, CIGS AROUND 8 KFT, AND GUSTY WINDS FROM THEIR
DIRECTION BETWEEN 30 AND 40 KTS. KBIH WILL EXPERIENCE A SECOND ROUND
OF VICINITY THUNDERSTORMS OVERNIGHT. WITHOUT THUNDERSTORM INFLUENCE,
EXPECT GUSTY SOUTHWEST WINDS AT LAS VEGAS VALLEY TAF SITES, GUSTY
SOUTH-SOUTHEAST WINDS AT KBIH, BREEZY NORTHWEST WINDS AT COLORADO
RIVER VALLEY TAF SITES, AND BREEZY EASTERLY WINDS AT KDAG.
THUNDERSTORM CHANCES RETURN TO THE REGION FRIDAY AFTERNOON.
SPOTTER INFORMATION STATEMENT
SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER OR IMPACTS ACCORDING TO STANDARD OPERATING
PROCEDURES.
DISCUSSION...MORGAN
AVIATION...SOULAT
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